1. Field of the Invention
The present invention relates to a rotary magnetic head device for a helical scanning magnetic recording and reproducing apparatus, comprising a rotary drum, a thin-film magnetic head protruding from the rotary drum in a diametrical direction for coming into contact with a magnetic tape, wound around part of the outer peripheral surface of the rotary drum, and head control means for adjusting the protrusion of the magnetic head in the diametrical direction.
2. Description of the Related Art
Such a rotary magnetic head device is known from U.S. Pat. No. 5,223,992. The device in this document is provided with an envelope detector for detecting an envelope of a reproduced signal from the magnetic head, search means, coupled to the envelope detector, for obtaining a minimum amount of projection of the magnetic head in a projection range in which a detected envelope level is saturated, by sequentially driving the magnetic head to vary the projection of the magnetic head, and control means for controlling the magnetic head to position the magnetic head at a projection which coincides with the minimum amount of projection obtained by the search means. In other words, the head control means comprises a feed-back control arrangement to bring and hold the magnetic head into a desired protruded position.